It's probably better if you have the hose pop off just in case your outlet volume suddenly increases e.g. the tank falls over, this way the gas doesn't purge into the tank.
I made one of these setups myself and I'd have to say that i'm really happy with the results, currently I'm waiting for a delivery on a 12v solenoid that I will mount on a T fitting that's normally open.
This way when the power is on it flows through to the tank and when the light turns off it diverts to inside my cabinet, a extra safety feature since if the power should cut for some reason the gas will just slowly purge.
This saves on fitting a noisy air pump that turns on after the light turns off, the price for the valve is $50NZD (roughly $40USD).
I am aware this is wasteful of the gas but it's so cheap to refill I'd rather do this than fit a high pressure valve on the bottle that costs alot more initially.
Also, to help a few of you guys I will point out that I used the gas rated thread tape and I had no leaks on my first setup, it's not white but yellow and is thicker, you can purchase it from most engineering suppliers that carry fittings.